US-20260126154-A1 - PLANAR LIGHT SOURCE AND THE METHOD OF MANUFACTURING THE SAME

US20260126154A1US 20260126154 A1US20260126154 A1US 20260126154A1US-20260126154-A1

Abstract

A planar light source includes light sources, an insulating base, a wiring layer, a light reflective member, and conducting members. The light sources each has electrodes extending on one face and a light adjusting member disposed on another face. The insulating base has a first side at which the light sources are located, and a second side on which the wiring layer is disposed. The light reflective member is located at the first side relative to the insulating base and defines first through holes at positions aligned with the electrodes, an opening of each of the first through holes not running over an outline of the light source. The conducting members are disposed in the first through holes and electrically connecting the electrodes to the wiring layer. The one face of each of the light sources has a region located between the electrodes and facing the light reflective member.

Inventors

Gensui TAMURA

Assignees

NICHIA CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251229
Priority Date: 20200413

Claims (20)

1 . A planar light source comprising: one or more light sources each having a pair of electrodes extending on one face of the one or more light sources within a perimeter of the one face of the one or more light sources and a light adjusting member disposed on another face opposite the one face of the one or more light sources in a plan view; an insulating base having a first side and a second side opposite each other relative to the insulating base, the first side at which the one or more light sources are located; a wiring layer electrically connected to the electrodes and disposed on the second side of the insulating base; a light reflective member located at the first side relative to the insulating base and defining, for each of the one or more light sources, a pair of first through holes at positions aligned with the electrodes on a one-to-one basis, an opening of each of the first through holes not running over an outline of the light source in the plan view; and for each of the one or more light sources, a pair of conducting members respectively disposed in the first through holes and electrically connecting the electrodes to the wiring layer, wherein the one face of each of the one or more light sources has a region located between the pair of electrodes and facing the light reflective member.
2 . The planar light source according to claim 1 , wherein— the one or more light sources include a light emitting element and a light transmissive member located between the light emitting element and the light adjusting member.
3 . The planar light source according to claim 2 , wherein— the light transmissive member includes a wavelength conversion member.
4 . The planar light source according to claim 1 , wherein— the light reflective member is a first light reflective member, and the planar light source further comprises a second light reflective member defining, for each of the one or more light sources, a second through hole at a position overlapping the first through holes in a plan view with the light source being disposed in the second through hole in the plan view.
5 . The planar light source according to claim 1 , wherein for each of the one or more light sources: a face of the wiring layer on a light reflective member side includes a pair of contact portions each facing a corresponding one of the first through holes; and each of the conducting members establishes electrical contact with a corresponding one of the contact portions.
6 . The planar light source according to claim 1 , wherein for each of the one or more light sources: the wiring layer defines a pair of third through holes communicating with the first through holes on a one-to-one basis; and each of the conducting members establishes electrical contact with the wiring layer at least on an inside of a corresponding one of the third through holes.
7 . The planar light source according to claim 6 , wherein for each of the one or more light sources, each of the conducting members further establishes the electrical contact with the wiring layer on a face of the wiring layer opposite a face facing the light reflective member.
8 . The planar light source according to claim 1 , wherein for each of the one or more light sources, each of the conducting members includes a first conducting member disposed in a corresponding one of the first through holes and a second conducting member disposed between the first conducting member and the wiring layer.
9 . The planar light source according to claim 1 , wherein the wiring layer disposed on the second face of the insulating base is covered by a cover layer.
10 . The planar light source according to claim 1 , wherein an opening of each of the first through holes for each of the one or more light sources has a shape that either substantially matches a shape of a corresponding one of the electrodes of the light source in the plan view, or extends within an outline of the corresponding one of the electrodes of the light source in the plan view.
11 . A planar light source comprising: one or more light sources each having a pair of electrodes extending on one face of the one or more light sources within a perimeter of the one face of the one or more light sources and a light adjusting member disposed on another face opposite the one face of the one or more light sources in a plan view; an insulating base having a first side and a second side opposite each other relative to the insulating base, the first side at which the one or more light sources are located; a wiring layer electrically connected to the electrodes and disposed on the second side of the insulating base; a light reflective member located at the first side relative to the insulating base and defining, for each of the one or more light sources, a pair of first through holes at positions aligned with the electrodes on a one-to-one basis, an opening of each of the first through holes not running over an outline of the light source in the plan view; and for each of the one or more light sources, a pair of conducting members respectively disposed in the first through holes and electrically connecting the electrodes to the wiring layer, wherein an opening of each of the first through holes for each of the one or more light sources extends within an outline of the light source in the plan view.
12 . The planar light source according to claim 11 , wherein— the one or more light sources include a light emitting element and a light transmissive member located between the light emitting element and the light adjusting member.
13 . The planar light source according to claim 12 , wherein— the light transmissive member includes a wavelength conversion member.
14 . The planar light source according to claim 11 , wherein— the light reflective member is a first light reflective member, and the planar light source further comprises a second light reflective member defining, for each of the one or more light sources, a second through hole at a position overlapping the first through holes in a plan view with the light source being disposed in the second through hole in the plan view.
15 . The planar light source according to claim 11 , wherein for each of the one or more light sources: a face of the wiring layer on a light reflective member side includes a pair of contact portions each facing a corresponding one of the first through holes; and each of the conducting members establishes electrical contact with a corresponding one of the contact portions.
16 . The planar light source according to claim 11 , wherein for each of the one or more light sources: the wiring layer defines a pair of third through holes communicating with the first through holes on a one-to-one basis; and each of the conducting members establishes electrical contact with the wiring layer at least on an inside of a corresponding one of the third through holes.
17 . The planar light source according to claim 16 , wherein for each of the one or more light sources, each of the conducting members further establishes the electrical contact with the wiring layer on a face of the wiring layer opposite a face facing the light reflective member.
18 . The planar light source according to claim 11 , wherein for each of the one or more light sources, each of the conducting members includes a first conducting member disposed in a corresponding one of the first through holes and a second conducting member disposed between the first conducting member and the wiring layer.
19 . The planar light source according to claim 11 , wherein the wiring layer disposed on the second face of the insulating base is covered by a cover layer.
20 . The planar light source according to claim 11 , wherein an opening of each of the first through holes for each of the one or more light sources has a shape that either substantially matches a shape of a corresponding one of the electrodes of the light source in the plan view, or extends within an outline of the corresponding one of the electrodes of the light source in the plan view.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application is a continuation application of the U.S. patent application Ser. No. 18/888,086 filed on Sep. 17, 2024, which is a continuation application of the U.S. patent application Ser. No. 17/963,904 filed on Oct. 11, 2022, now U.S. Pat. No. 12,111,024, which is a divisional application of the U.S. patent application Ser. No. 17/227,827 filed on Apr. 12, 2021, now U.S. Pat. No. 11,499,684. This application claims priority to Japanese Patent Application No. 2020-071742 filed on Apr. 13, 2020, and Japanese Patent Application No. 2021-037887 filed on Mar. 10, 2021, the disclosures of which are hereby incorporated by reference in their entireties. BACKGROUND The present disclosure relates to a planar light source and the method of manufacturing the same. Planar light sources which employ light emitting diodes as light sources are used in many devices such as backlights for liquid crystal display televisions. It is necessary to effectively utilize the light from such a light source in order to increase the luminance and reduce the power consumption of the planar light source. For example, Japanese Unexamined Patent Application Publication No. 2019-003994 discloses a technique to increase the light extraction efficiency of a light emitting device in which a light emitting element is connected using wires that are exposed. SUMMARY One of the objects of the present disclosure is to provide a planar light source capable of hindering the wiring material from absorbing the light from a light source and a method of manufacturing the same. A planar light source according to the present disclosure includes one or more light sources, an insulating base, a wiring layer, a light reflective member, and a pair of conducting members for each of the one or more light sources. The one or more light sources each has a pair of electrodes extending on one face of the one or more light sources within a perimeter of the one face of the one or more light sources and a light adjusting member disposed on another face opposite the one face of the one or more light sources in a plan view. The insulating base has a first side and a second side opposite each other relative to the insulating base, the first side at which the one or more light sources are located. The wiring layer is electrically connected to the electrodes and disposed on the second side of the insulating base. The light reflective member is located at the first side relative to the insulating base and defining, for each of the one or more light sources, a pair of first through holes at positions aligned with the electrodes on a one-to-one basis, an opening of each of the first through holes not running over an outline of the light source in the plan view. The pair of conducting members are respectively disposed in the first through holes and electrically connecting the electrodes to the wiring layer. The one face of each of the one or more light sources has a region located between the pair of electrodes and facing the light reflective member. According to the present disclosure, a planar light source capable of more effectively utilizing the emitted light from a light source by hindering the wiring material from absorbing light, and a method of manufacturing the same can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a planar light source according to a first embodiment. FIG. 2 is a schematic cross-sectional view taken along a line II-II in FIG. 1. FIG. 3A is a schematic perspective view illustrating a light source according to the first embodiment. FIG. 3B is a schematic cross-sectional view taken along a line IIIB-IIIB in FIG. 3A. FIG. 3C is a schematic bottom view of the light source in FIG. 3A showing the face having electrodes. FIG. 4 is a schematic plan view of the opening in the cover layer of the wiring substrate according to the first embodiment. FIG. 5 is a schematic perspective view of a light emitting module according to the first embodiment. FIG. 6 is a schematic plan view showing the relative positions of the light sources and the light reflecting members according to the first embodiment. FIG. 7A is a schematic cross-sectional view illustrating a manufacturing method according to the first embodiment. FIG. 7B is a schematic cross-sectional view illustrating the manufacturing method according to the first embodiment. FIG. 7C is a schematic cross-sectional view illustrating the manufacturing method according to the first embodiment. FIG. 7D is a schematic cross-sectional view illustrating the manufacturing method according to the first embodiment. FIG. 7E is a schematic cross-sectional view illustrating the manufacturing method according to the first embodiment. FIG. 7F is a schematic cross-sectional view illustrating the manufacturing method according to the first embodiment. FIG. 8A is a schematic cross-sectional view illustrating the manufacturing method accordi